#include <iostream>
#include <stdio.h>
#include "opencv2/core.hpp"
#include "opencv2/core/utility.hpp"
#include "opencv2/core/ocl.hpp"
#include "opencv2/imgcodecs.hpp"
#include "opencv2/highgui.hpp"
#include "opencv2/features2d.hpp"
#include "opencv2/calib3d.hpp"
#include "opencv2/imgproc.hpp"
#include"opencv2/flann.hpp"
#include"opencv2/xfeatures2d.hpp"
#include"opencv2/ml.hpp"

using namespace cv;
using namespace std;
using namespace cv::xfeatures2d;
using namespace cv::ml;

int main(int argc ,char ** argv)
{
	int width =0 ;
	int height =0 ;
	if(argc < 3){
		cout <<"usage: ./surf img1 img2 width height"<<endl;
		return -1 ;
	}
    Mat a = imread(argv[1], IMREAD_GRAYSCALE);    //读取灰度图像
    Mat b = imread(argv[2], IMREAD_GRAYSCALE);

    stringstream ss;
    ss<<argv[3];
    ss>>width ;
    ss.clear();
    ss<<argv[4];
    ss>>height ;

	cv::resize(a, a, cv::Size(width,height), (0, 0), (0, 0), cv::INTER_LINEAR);
	cv::resize(b, b, cv::Size(width,height), (0, 0), (0, 0), cv::INTER_LINEAR);


    Ptr<SURF> surf;      //创建方式和2中的不一样
    surf = SURF::create(800);

    BFMatcher matcher;
    Mat c, d;
    vector<KeyPoint>key1, key2;
    vector<DMatch> matches;

    surf->detectAndCompute(a, Mat(), key1, c);
    surf->detectAndCompute(b, Mat(), key2, d);

    matcher.match(c, d, matches);       //匹配
    cout<<"match size:"<<matches.size()<<endl;

    sort(matches.begin(), matches.end());  //筛选匹配点
    vector< DMatch > good_matches;
    int ptsPairs = std::min(50, (int)(matches.size() * 0.15));
    cout << ptsPairs << endl;
    for (int i = 0; i < ptsPairs; i++)
    {
        good_matches.push_back(matches[i]);
    }
    Mat outimg;
    drawMatches(a, key1, b, key2, good_matches, outimg, Scalar::all(-1), Scalar::all(-1),vector<char>(), DrawMatchesFlags::NOT_DRAW_SINGLE_POINTS);  //绘制匹配点

    std::vector<Point2f> obj;
    std::vector<Point2f> scene;

    for (size_t i = 0; i < good_matches.size(); i++)
    {
        obj.push_back(key1[good_matches[i].queryIdx].pt);
        scene.push_back(key2[good_matches[i].trainIdx].pt);
    }

    std::vector<Point2f> obj_corners(4);
    obj_corners[0] = Point(0, 0);
    obj_corners[1] = Point(a.cols, 0);
    obj_corners[2] = Point(a.cols, a.rows);
    obj_corners[3] = Point(0, a.rows);
    std::vector<Point2f> scene_corners(4);

    Mat H = findHomography(obj, scene, RANSAC);      //寻找匹配的图像
    perspectiveTransform(obj_corners, scene_corners, H);

    line(outimg,scene_corners[0] + Point2f((float)a.cols, 0), scene_corners[1] + Point2f((float)a.cols, 0),Scalar(0, 255, 0), 2, LINE_AA);       //绘制
    line(outimg,scene_corners[1] + Point2f((float)a.cols, 0), scene_corners[2] + Point2f((float)a.cols, 0),Scalar(0, 255, 0), 2, LINE_AA);
    line(outimg,scene_corners[2] + Point2f((float)a.cols, 0), scene_corners[3] + Point2f((float)a.cols, 0),Scalar(0, 255, 0), 2, LINE_AA);
    line(outimg,scene_corners[3] + Point2f((float)a.cols, 0), scene_corners[0] + Point2f((float)a.cols, 0),Scalar(0, 255, 0), 2, LINE_AA);
    imshow("outimg",outimg);
    cvWaitKey(0);
}
